In the prior art, as a pillow that enables a person to sleep properly, patent document 1 discloses a pillow having the following structure. The pillow includes a back head fit line arranged in the widthwise direction to stably hold the back of the head at the middle of a head support portion. A neck support portion is arranged at a lower side of the head support portion. Further, the pillow includes side portions arranged at the left and right sides of the head support portion and the neck support portion. The lower peripheral parts of the two side portions form a shoulder fit line. The support portions and the side portions are each bag-like and are filled with fillings such as wool knops, piping material, and beads material.
In such a pillow, the back head fit line formed in the head support portion improves the support of the head with the pillow and enables smooth movement of the head when a sleeping person rolls over. Further, the shoulder fit line enables the pillow to fit with the shoulder line. Thus, an integral feel with the pillow and mental relaxation can be expected.
In the above pillow of the prior art, the back head fit line is formed by joining the front and rear covers of the head support portion in the widthwise direction so as to form a constricted part with a narrow and shallow groove. Fillings do not exist in the portion corresponding to the back head fit line. Further, this portion is not resilient. Accordingly, the above prior art pillow does not function to sufficiently support the head. Further, the head support portion does not deform sufficiently so as to follow movement of the head in the left and right directions. Thus, a sleeping person cannot smoothly move his or her head when rolling over. Further, in the above prior art pillow, the two side portions are higher than the head support portion and the neck support portion. This makes it difficult for a sleeping person to roll over smoothly. Moreover, the side of the head is only supported by the upper surface of the side portions when a sleeping person rolls over. Thus, the side of the head cannot be stably supported.
Patent Document 1: Registered Utility Model No. 3109464